Conventional non-spherical resin particles are known that are composed of two or more different resin components.
Patent Document 1, as an example, describes use of a phase separation mechanism in a method in which a mixture is prepared by mixing: a polymer compound obtained by polymerization of a methacrylic acid ester; a methacrylic acid ester; and a radical polymerization initiator, and the mixture is subjected to suspension polymerization in an aqueous solution containing a dissolved dispersion stabilizer. Examples 8 and 9 given in the document produce acrylic resin particles with dimples, shaped overall like golf balls. Example 10 produces partially porous acrylic resin particles with numerous less-than-1-micrometer dents.
Another example, Patent Document 2, describes fine spherical polymer particles with a regularly creased surface being produced by dissolving a styrene-based elastomer in a mixture of a hydrophobic polymerizable vinyl monomer and a crosslinking monomer and subjecting the dissolved elastomer to suspension polymerization in an aqueous medium.